I notice that the druid earth tree cuts off at level 22, so I have some suggestions for a couple of higher level druid earth spells. These are very much inspired by earthbending from Avatar: The Last Airbender (the cartoon, not the crap movie).

shockwave -- the druid stomps or punches the ground, causing a rippling shockwave to blast out towards a land bound target. The ground breaks up and explodes beneath the target's feet, doing damage and possibly knocking them back, causing them slight lag as they regain their footing.

This is basically a limited, highly targeted version of earthquake, and should be level 30+.

landslide -- this spell only works when the druid has an earth wall active. The druid slams his fists into the earth wall, causing itto propel forward, crumbling as it goes. Any targets caught in the path take damage and have a chance to be knocked down (has a chanceto hit multiple targets in rapid succession). This spell has a high mana cost, but the damage output is high as well.

This can be handled in two ways -- the earth wall can be destroyed by one casting the spell, or each casting can do a large chunk ofdamage to it as pieces of it are shot forward until it is used up. I feel this is the stronger of these two suggestions.

So there's this gap in the air tree -- the solar lensing branch starts off at level 32, based on a level 1 spell, gust of wind. I would think there would be a step between blasting someone with a gust of air and creating enormous air vortices hundreds of feet over head to focus sunlight.

So here's one idea:

air burst - the druid compresses a large amount of air into a high pressure sphere, then hurls it enemies. It violently expands on contact, doing concussive damage.The spell takes a moment to charge like rotting sphere, and has a chance to damage nearby enemies like greater fireball. Similar to gust of wind, the primary target might get knocked down and airborne targets are extra vulnerable.

An additional side effect (mobs only) may be:

Sufficiently small enemies may be knocked into an adjacent room (only if all rooms involved are not flagged BIG and the mobs are normally moveable, i.e. NO_CHARM, NO_GET flags prevent any movement).

The spell would have a moderately high mana cost, due to its difficulty and debuff side effects. It would be in the level 21-26 range.

Here's another idea:

snow blast - this sky spell enchants a gathered snowball to explode like an icy grenade when thrown. It functions in a manner similar to thunder seeds. Might be obscure.

The druid causes thorny briars to wrap around his body. Enemies have a chance to take a small amount of piercing damage each time they strike him until the spell expires. The druid retains partial control over the briars so can loosen to allow equipment to be swapped out, complex combat skills to be performed, etc.